Multi-bladed rotary cutting decks are known which have dual, side-by-side cutting chambers. Each cutting chamber encloses a cutting blade that is rotatable about a substantially vertical axis such that the cutting blade rotates in a substantially horizontal cutting plane. The blades rotate oppositely to one another such that the grass clippings generated by each cutting blade merge together into a common grass clipping stream. A rearwardly extending and rearwardly opening exit tunnel on the cutting deck receives this grass clipping stream to allow the stream to exit to the rear of the cutting deck, either for discharge onto the ground or for collection in a grass bagging apparatus. Thus, the cutting deck has a first discharge/collection mode of operation when the exit tunnel is open and permits the grass clipping stream to exit from the cutting deck.
Known rotary cutting decks of the type described above can be converted to a mulching mode of operation in which the grass clipping stream is prevented from passing through the exit tunnel. In this mulching mode, the grass clipping stream is confined within the cutting chambers to allow the grass clippings to be recut. Eventually, the grass clippings either fall or are driven out of the cutting chambers in a downward direction through the open bottom of the cutting chambers. The rotary cutting deck is converted or switched to the mulching mode of operation by selectively closing off the exit tunnel on the deck so that the grass clipping stream can no longer pass through the exit tunnel.
In converting a rotary cutting deck of the type described above to its mulching mode of operation, a separate mulching plug is typically used which must be inserted through the open rear end of the exit tunnel to block or close off the exit tunnel. This can be difficult to do given the placement of the cutting deck relative to the rest of the mower and given the fact that the exit tunnel is in the center of the deck along a rear side of the deck and is not at the side of the deck. Thus, converting the rotary cutting deck to the mulching mode by manually inserting a plug into the exit tunnel is not as easy as would be desirable.
Moreover, the conversion of the rotary cutting deck to the mulching mode means that the mulching plug must be on hand and available to the user or operator. If the user or operator of the rotary cutting deck is out in the field cutting grass when he or she wishes to make the conversion between the discharge/collection mode and the mulching mode, this can be done only if the mulching plug is actually being carried on the mower. The mulching plug is most likely back at the shop or garage. This requires that the operator go back to the shop or garage to pick up the mulching plug before the rotary cutting deck can be converted to the mulching mode of operation. This is obviously a disadvantage of a system that requires a separate mulching plug to convert the rotary cutting deck to the mulching mode.
In addition, the mulching plug is prone to being lost or misplaced. If this happens, the operator cannot convert the rotary cutting deck to the mulching mode without finding or replacing the mulching plug. Again, this can be inconvenient and annoying.